Ceramic oxide materials having high temperature, superconductive characteristics are priorly known as those materials whose transition to superconduction occur at temperatures of 100.degree. Kelvin and above. Although it has been priorly suggested to apply a thin layer of such materials comprised of mixed oxides of yttrium, barium and copper to the surfaces of copper wires, the brittle and inflexible characteristics of such layers have resulted in unacceptable mechanical damage in the manufacture and use of cables including wires so covered.